From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Report from Ransome & Marles Bearing Co. on bearing test results, specifically detailing the 'Sixth Test'.
| Identifier | ExFiles\Box 114\2\ scan0033 | |
| Date | 6th April 1934 | |
| RANSOME & MARLES BEARING Co., Ltd. - 3 - Messrs. Rolls-Royce, Limited, D E R B Y . 6-4-34. behaviour of our standard brass cage under running conditions similar to the fourth test, using Whitmore oil, the loads being lower than before in view of the fact that a standard MDJT.30 was used, and the test was primarily concerned with the effect on the cage and not on the tracks. After a run of nine hours, equivalent to the fourth test, the brass cage was in perfect condition, as well as the shoulders of the inner, and therefore, a duralumin cage was fitted to the same bearing, and the run continued for a further eighty-nine hours, and here again, no signs of cage wear or wear on the shoulder of the inner were apparent. SIXTH TEST : A Hoffmann bearing No. 245 was tested under the same conditions as the first to fourth tests, viz: 2840 lbs. thrust and 2100 lbs. journal, at 3000 r.p.m., but with the mounting as advised by Hoffmann and adopted by you originally, a continuous supply of oil being provided. After twenty-four hours, the row of balls under thrust had caused a slight failure in the outer track, this being a typical overload failure, and it was interesting to note that on this test, a very definite indication of the inadvisability of locating both the outers in the housing was evident, the track which was under thrust indicating that it had also taken the whole of the journal load, while the track which was not under thrust shewed very definitely that the balls had done no work whatever. Incidentally, this bearing is a double row double purpose bearing of very similar design to our MDJT.30. | ||